My invention relates to an electric lighting fixture and in particular to a fluorescent fixture using a standard voltage U-shaped fluorescent lamp designed for outdoor use and constructed mainly of polyvinyl chloride resin.
Up to now, for various reasons, almost all electric lighting fixture housings and fittings have been made of metal. One reason is that metals do not deteriorate or deform as the result of the high temperatures generated within a lighting fixture by incandescent 110 volt lamps used in conventional lighting fixtures. However, for lighting fixtures designed for use out-of-doors, most metal housings and fittings are subject to rapid corrosion due to constant exposure to rain and sun and, in coastal areas, to salt spray, even when the metal parts are temporarily protected by paint. Moreover, recent increases in the price of metals and in fabricating costs have resulted in increases in the prices of conventional lighting fixtures with housings and fittings made of metal.
The present trend to reduce energy consumption has resulted in increased use of low voltage lamps, that is, incandescent lamps which operate at voltages considerably less than 110 volts. These low voltage lamps, particularly 12 volt incandescent lamps, generate far less heat in operation than 110 volt lamps.
My prior patent application Ser. No. 623,319 filed June 22, 1984, pointed out that it was possible to construct a very satisfactory outdoor lighting fixture for use with a low voltage incandescent lamp which has a housing and essentially all its components made of polyvinyl chloride resin. Such a lighting fixture is less expensive to manufacture and more durable than conventional outdoor fixtures using incandescent lamps.
I have now developed a unique outdoor lighting fixture using a standard voltage U-shaped fluorescent lamp. This novel fixture includes ten major components as follows: a cylindrical housing having at its center an interior annular ring preferably made entirely of white high density polyvinyl chloride resin (hereinafter often referred to as PVC); a U-shaped fluorescent lamp; a socket for said lamp; a circular base supporting said socket having an outer diameter slightly less than the inside diameter of the cylindrical housing; a 120 volt transformer mounted on the base; a retaining ring having an outer diameter slightly less than the inside diameter of the housing; a closed-ended tubular transparent diffuser having a diameter somewhat less than the inner diameter of the housing; a pair of flexible O-rings for securing the diffuser to the housing; and a circular bushing preferably made of PVC for sealing the rear of the housing and containing an annular opening for the electric wires connected to energize the U-shaped fluorescent lamp.
As assembled, the base supporting the lamp, socket and transformer is seated on the upper edge of the interior ring of the cylindrical housing. Then the retaining ring is seated on the upper edge of the base. Next the two O-rings are slipped over the open end of the tubular diffuser. Then the open end of the diffuser is firmly pressed into the upper end of the cylindrical housing and secured within the housing by the two compressed O-rings. The electric wires connected to energize the lamp are contained within a tubular conduit which enters the fixture through the annular opening in the circular bushing that seals the rear of the housing.
As mentioned in my aforesaid prior application, there are a number of prior suggestions in the art to use various plastic and elastomeric resins in the fabrication of lighting fixture components. These suggestions include U.S. Pat. Nos. 3,902,057; 4,210,841; 4,360,862; 4,379,321; 4,380,793 and 4,414,613. However, my outdoor lighting fixture using a standard voltage U-shaped fluorescent lamp possesses the following advantages over conventional outdoor fixtures:
1. Because most of its components are already available in quantity, the cost of its components is lower than the cost of conventional fixture components.
2. Because its components can be quickly assembled by unskilled labor, my lighting fixture costs less to manufacture than conventional fixtures.
3. Because it utilizes a standard voltage fluorescent lamp which generates very little heat and its housing is constructed of white high density polyvinyl chloride resin, the housing will not deteriorate or deform in operation.
4. Because its housing and most of the fittings are made of white high density polyvinyl chloride resin, the fixture is literally impervious to the deleterious effects of sun, rain and salt spray even in tropical climates.